Unless someone says otherwise convincingly, I intend to warm up the nectar to 98 – 100 degrees Fahrenheit in a pot before offering it in the feeder. I have read that microwaving changes molecular structure. Dunno about that, but I am not willing to risk it.
I think Anna’s Hummingbirds must be relatively robust compared to other hummingbirds, so do not despair. Thaw out or replace the nectar as quickly as you can to give them a better chance.
